Rethinking the Computer Enhanced Design Process

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What is a design method?

• A design method is a semi-formalized procedure
  for designing something.

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What is a design method?

• A design method is a semi-formalized procedure
  for designing something.

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Design methods vs. Design strategies

• Design methods are not the same as design
  strategies

• A design strategy focuses on the design form. It
  suggests a design solution to a particular design
  problem
• General rules for the building form
• Templates for the building form
• Guidelines for the building form
• A design method focuses on the process. It
  suggests a design procedure to follow for
  particular types of design problems
• General rules for the process
• Templates for the process
• Guidelines for the process

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Types of CAAD Method

• There are three types of CAAD Method

• Drawing these methods automate the process of
  creating drawing, in particular technical
  construction drawings. (e.g. AutoCAD)
• Modelling these methods explore new formal
  possibilities by playing with three-dimensional
  models. For example, blob architecture. (e.g.
  Greg Lynn)
• Decision making these methods use the computer
  to help designers make decisions during the
  design process.

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The role of the computer

• In decision making, the computer can play a
  number of important roles. Three important roles
  are

• The generative role is the most ambitious the
  designer provides the computer with initial data,
  and the computer then autonomically generates
  alternative designs.
• In the expert role, the computer acts as an
  expert in a very specialist area. The types of
  problems within the design process that can be
  solved by expert systems are very limited.
• The evaluative role is more humble, and also more
  realistic. In this role, the computer evaluates
  the designs produced by the designer.

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Atlas Titan at Cambridge University
1970
2040
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Building performance simulation

• Building performance is the key concept
• Performance targets
• Performance evaluation

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Conventional design process

• Building performance can be predicted using
• Rules of thumb
• General guidelines
• Templates
• Simplified assumptions

• These traditional methods have many deficiencies
• Simplified assumptions are often incorrect.
• Not explicit.
• Not accurate.

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What is a simulation?

• Building performance can be predicted using
  simulation software

• Developing a (simplified) model of a complex
  system, and using the model to analyse and
  predict the behaviour of the original system.
• In design, simulations are used to evaluate a
  design.
• A simulation will not tell you how to improve the
  design!

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What is a simulation?

• The simulation attempts to predict how the
  building would perform if built.

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What can be evaluated?

• Many different types of software system have been
  developed to evaluate buildings. For example

• Environmental impact analysis (e.g. embodied
  energy within materials)
• Cost analysis (e.g. fabric cost calculation)
• Structural analysis (e.g. structural stability)
• Environmental simulation (e,g, lighting, energy,
  acoustics)
• User behaviour simulation (e.g. people flow)

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Potential benefits

• Results in buildings with better quality (indoor)
  environment. This leads to improvements in

• Comfort
• Health
• Productivity

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Potential benefits

• Results in buildings that consume less energy.
  This leads to

• A reduced electricity / gas / other energy bill.
• A more healthy planet.
• Moderating the internal environment accounts for
  over 25 of energy consumption.

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Potential benefits

• Results in designers understanding the issues
  involved.

• Experimental rather than theoretical approach.
• Visual and graphical feedback .
• Learning and understanding
• Or maybe not!

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Potential problems

• There are also a number of problems with using
  simulation software

• It changes the way that the design must be
  modelled
• It is complex to learn requires a lot of
  knowledge
• It favours conventional building types
• Is restricted in the types of geometries that can
  be modelled
• It can be inaccurate

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Lighting and energy

• This course will focus on the simulation of
• The performance of the building in terms of
  lighting daylight, sunlight and electric
  lighting within buildings.
• The performance of the building in terms of
  energy the energy used for heating, ventilation
  and cooling of a building.

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Lighting

• Main design issues
• Light sources day lighting, sun lighting, and
  artificial lighting
• Distribution of light within a space
• Material shade and colour
• Reflectors
• Glare

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Energy

• Main design issues
• Heating, ventilation and air-conditioning (HVAC)
• Heat sources people, lighting, solar gain
• Psychrometrics and human comfort
• Materials Thermal resistance and conductivity
• Climate

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Problems

• Simulation systems are more demanding than
  traditional CAD packages

• They are less forgiving the data has to be
  entered in a very precise way
• Interoperability with other CAD systems tends to
  be very limited
• They tend to restrict the types of geometries
  that can be simulated
• They tend to be design for simulating very
  conventional buildings

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Problems

• One of the key problems with these systems is
  getting the data for the simulation into the
  system.
• They typically require five types of information

• Context topography, surrounding structures,
  weather data.
• Geometry components and spaces.
• Materials visual, thermophysical, acoustic.
• Systems heating, ventilation, air-conditioning,
  artificial lighting.
• Occupancy number of people, activities,
  schedules, equipment.

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More problems

• In addition, there are some other common
  problems

• They require much more knowledge from the user
• Their user interfaces are often very rudimentary
• They are limited in what they can simulate, for
  example they can usually not simulate user
  behaviour

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So many problems.

• Let the engineer do it!

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Role of the engineer

• Traditional approach to building simulation

conceptdesign
detaileddesign
brief
building
designsimulation
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Role of the engineer

• Previously, environmental simulation of building
  performance was only done by engineers at the end
  of the design process. Any weak points in the
  performance of the design could then be fixed
  by adding heating, cooling, shades, vents, fanes,
  panels, etc

• However
• The end of the design process is too late!!!
• The decisions made early on in the design process
  have the largest impact
• In addition
• Environmental issues are becoming more important
• The complexity of the building design is
  increasing
• Simulation tools are becoming more architect
  friendly (?)

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Role of the architect

• Alternative approach to building simulation

conceptdesign
detaileddesign
brief
building
designsimulation
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Role of the architect

• Simulation tools have become
• Faster
• Cheaper
• Less complex
• More user friendly

• As a result, simulation tools
• Allow designers to study matters not previously
  considered in many building design processes

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Simulation process

• Simulation consists of three steps
• Create a model of the design
• Running the simulation
• Analyse and interpret the design

• After simulation, the designer must modify the
  design and then possibly re-run the simulation
• Modify the design
• The four steps can be summarised as follows
• Model
• Simulate
• Analyse
• Modify

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Linear method

• One type of design method

modify design
simulate design
analyse results
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Parallel method

• Another type of design method

analyse results
option
simulate design
analyse results
option
simulate design
analyse results
option
simulate design
option
simulate design
analyse results
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Conflicting design issues

• Problem
• The design modifications required by different
  simulations may conflict
• For example
• The lighting simulation may indicate that the
  roof lights should be bigger
• The energy simulation may indicate that the roof
  lights should be smaller

• Designers job
• Find a balance
• Compromise

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Ecotect
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Characteristics of simulation tools

• Simulation tools may either focus on just one
  aspect, or they may focus on a number of aspects
  that are interrelated.
• Simple tools focus on one or two aspects.
• Integrative tools focus on a number of aspects.

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Characteristics of simulation tools

• Simple tools
• CATT-Acoustics (acoustics)
• Desktop Radiance (lighting)
• SolArch (thermal)

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Characteristics of simulation tools

• Integrative tools
• Solar 5.7 (daylighting and energy)
• Building Design Advisor (lighting and energy)
• ESP-r (lighting and energy)
• Design Builder (lighting and energy)
• eQUEST (energy)
• ECOTECT (acoustics, lighting and energy)

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The environment